Weird web browser problem

[silymac]

Hello, for some reason in all web browsers I try - Chrome, Safari, Firefox - I have the same 'boxes' come on the screen when my mouse scrolls over certain parts of the browser window. It is always the same words as well, examples include Amazon, ebay, dow jones industrial average, nasdaq. They are always the same words in the same place no matter what browser, or where the browser window is located on my desktop. I attached screenshots which hopefully make sense of what I am saying. The only thing I could think of was to reset the browsers, which I do regularly, with no effect. Any help on how to get rid of these would be very appreciated. Thank you.